src/msw/ole/droptgt.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        ole/droptgt.cpp
   3 // Purpose:     wxDropTarget implementation
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
   9 // Licence:     wxWindows license
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // Declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #ifdef __GNUG__
  21 #pragma implementation "droptgt.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #if defined(__BORLANDC__)
  28 #pragma hdrstop
  29 #endif
  30
  31 #include "wx/setup.h"
  32
  33 #if wxUSE_DRAG_AND_DROP
  34
  35 #include "wx/log.h"
  36
  37 #ifdef __WIN32__
  38     #ifndef __GNUWIN32__
  39         #include <shlobj.h>            // for DROPFILES structure
  40     #endif
  41 #else
  42     #include <shellapi.h>
  43 #endif
  44
  45 #include "wx/dnd.h"
  46
  47 #ifndef __WIN32__
  48     #include <ole2.h>
  49     #include <olestd.h>
  50 #endif
  51
  52 #include "wx/msw/ole/oleutils.h"
  53
  54 // ----------------------------------------------------------------------------
  55 // IDropTarget interface: forward all interesting things to wxDropTarget
  56 // (the name is unfortunate, but wx_I_DropTarget is not at all the same thing
  57 //  as wxDropTarget which is 'public' class, while this one is private)
  58 // ----------------------------------------------------------------------------
  59
  60 class wxIDropTarget : public IDropTarget
  61 {
  62 public:
  63     wxIDropTarget(wxDropTarget *p);
  64     // suppress gcc warning
  65 #ifdef __GNUG__
  66     virtual
  67 #endif
  68     ~wxIDropTarget();
  69
  70     // accessors for wxDropTarget
  71     void SetHwnd(HWND hwnd) { m_hwnd = hwnd; }
  72
  73     // IDropTarget methods
  74     STDMETHODIMP DragEnter(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  75     STDMETHODIMP DragOver(DWORD, POINTL, LPDWORD);
  76     STDMETHODIMP DragLeave();
  77     STDMETHODIMP Drop(LPDATAOBJECT, DWORD, POINTL, LPDWORD);
  78
  79     DECLARE_IUNKNOWN_METHODS;
  80
  81 protected:
  82     IDataObject  *m_pIDataObject; // !NULL between DragEnter and DragLeave/Drop
  83     wxDropTarget *m_pTarget;      // the real target (we're just a proxy)
  84
  85     HWND          m_hwnd;         // window we're associated with
  86
  87     // get default drop effect for given keyboard flags
  88     static inline DWORD GetDropEffect(DWORD flags);
  89 };
  90
  91 // ----------------------------------------------------------------------------
  92 // private functions
  93 // ----------------------------------------------------------------------------
  94
  95 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect);
  96 static DWORD ConvertDragResultToEffect(wxDragResult result);
  97
  98 // ============================================================================
  99 // wxIDropTarget implementation
 100 // ============================================================================
 101
 102 // Name    : static wxIDropTarget::GetDropEffect
 103 // Purpose : determine the drop operation from keyboard/mouse state.
 104 // Returns : DWORD combined from DROPEFFECT_xxx constants
 105 // Params  : [in] DWORD flags       kbd & mouse flags as passed to
 106 //                                  IDropTarget methods
 107 // Notes   : We do "move" normally and "copy" if <Ctrl> is pressed,
 108 //           which is the standard behaviour (currently there is no
 109 //           way to redefine it)
 110 DWORD wxIDropTarget::GetDropEffect(DWORD flags)
 111 {
 112   return flags & MK_CONTROL ? DROPEFFECT_COPY : DROPEFFECT_MOVE;
 113 }
 114
 115 wxIDropTarget::wxIDropTarget(wxDropTarget *pTarget)
 116 {
 117   m_cRef         = 0;
 118   m_pTarget      = pTarget;
 119   m_pIDataObject = NULL;
 120 }
 121
 122 wxIDropTarget::~wxIDropTarget()
 123 {
 124 }
 125
 126 BEGIN_IID_TABLE(wxIDropTarget)
 127   ADD_IID(Unknown)
 128   ADD_IID(DropTarget)
 129 END_IID_TABLE;
 130
 131 IMPLEMENT_IUNKNOWN_METHODS(wxIDropTarget)
 132
 133 // Name    : wxIDropTarget::DragEnter
 134 // Purpose : Called when the mouse enters the window (dragging something)
 135 // Returns : S_OK
 136 // Params  : [in] IDataObject *pIDataSource : source data
 137 //           [in] DWORD        grfKeyState  : kbd & mouse state
 138 //           [in] POINTL       pt           : mouse coordinates
 139 //           [out]DWORD       *pdwEffect    : effect flag
 140 // Notes   :
 141 STDMETHODIMP wxIDropTarget::DragEnter(IDataObject *pIDataSource,
 142                                       DWORD        grfKeyState,
 143                                       POINTL       pt,
 144                                       DWORD       *pdwEffect)
 145 {
 146     wxLogDebug(wxT("IDropTarget::DragEnter"));
 147
 148     wxASSERT( m_pIDataObject == NULL );
 149
 150     if ( !m_pTarget->IsAcceptedData(pIDataSource) ) {
 151         // we don't accept this kind of data
 152         *pdwEffect = DROPEFFECT_NONE;
 153
 154         return S_OK;
 155     }
 156
 157     // get hold of the data object
 158     m_pIDataObject = pIDataSource;
 159     m_pIDataObject->AddRef();
 160
 161     // we need client coordinates to pass to wxWin functions
 162     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 163     {
 164         wxLogLastError(wxT("ScreenToClient"));
 165     }
 166
 167     // give some visual feedback
 168     *pdwEffect = ConvertDragResultToEffect(
 169                     m_pTarget->OnEnter(pt.x, pt.y,
 170                         ConvertDragEffectToResult(GetDropEffect(grfKeyState))
 171                     )
 172                  );
 173
 174     return S_OK;
 175 }
 176
 177 // Name    : wxIDropTarget::DragOver
 178 // Purpose : Indicates that the mouse was moved inside the window represented
 179 //           by this drop target.
 180 // Returns : S_OK
 181 // Params  : [in] DWORD   grfKeyState     kbd & mouse state
 182 //           [in] POINTL  pt              mouse coordinates
 183 //           [out]LPDWORD pdwEffect       effect flag
 184 // Notes   : We're called on every WM_MOUSEMOVE, so this function should be
 185 //           very efficient.
 186 STDMETHODIMP wxIDropTarget::DragOver(DWORD   grfKeyState,
 187                                      POINTL  pt,
 188                                      LPDWORD pdwEffect)
 189 {
 190     // there are too many of them... wxLogDebug("IDropTarget::DragOver");
 191
 192     wxDragResult result;
 193     if ( m_pIDataObject ) {
 194         result = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 195     }
 196     else {
 197         // can't accept data anyhow normally
 198         result = wxDragNone;
 199     }
 200
 201     // we need client coordinates to pass to wxWin functions
 202     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 203     {
 204         wxLogLastError(wxT("ScreenToClient"));
 205     }
 206
 207     *pdwEffect = ConvertDragResultToEffect(
 208                     m_pTarget->OnDragOver(pt.x, pt.y, result)
 209                  );
 210
 211     return S_OK;
 212 }
 213
 214 // Name    : wxIDropTarget::DragLeave
 215 // Purpose : Informs the drop target that the operation has left its window.
 216 // Returns : S_OK
 217 // Notes   : good place to do any clean-up
 218 STDMETHODIMP wxIDropTarget::DragLeave()
 219 {
 220   wxLogDebug(wxT("IDropTarget::DragLeave"));
 221
 222   // remove the UI feedback
 223   m_pTarget->OnLeave();
 224
 225   // release the held object
 226   RELEASE_AND_NULL(m_pIDataObject);
 227
 228   return S_OK;
 229 }
 230
 231 // Name    : wxIDropTarget::Drop
 232 // Purpose : Instructs the drop target to paste data that was just now
 233 //           dropped on it.
 234 // Returns : S_OK
 235 // Params  : [in] IDataObject *pIDataSource     the data to paste
 236 //           [in] DWORD        grfKeyState      kbd & mouse state
 237 //           [in] POINTL       pt               where the drop occured?
 238 //           [ouy]DWORD       *pdwEffect        operation effect
 239 // Notes   :
 240 STDMETHODIMP wxIDropTarget::Drop(IDataObject *pIDataSource,
 241                                  DWORD        grfKeyState,
 242                                  POINTL       pt,
 243                                  DWORD       *pdwEffect)
 244 {
 245     wxLogDebug(wxT("IDropTarget::Drop"));
 246
 247     // TODO I don't know why there is this parameter, but so far I assume
 248     //      that it's the same we've already got in DragEnter
 249     wxASSERT( m_pIDataObject == pIDataSource );
 250
 251     // by default, nothing happens
 252     *pdwEffect = DROPEFFECT_NONE;
 253
 254     // we need client coordinates to pass to wxWin functions
 255     if ( !ScreenToClient(m_hwnd, (POINT *)&pt) )
 256     {
 257         wxLogLastError(wxT("ScreenToClient"));
 258     }
 259
 260     // first ask the drop target if it wants data
 261     if ( m_pTarget->OnDrop(pt.x, pt.y) ) {
 262         // it does, so give it the data source
 263         m_pTarget->SetDataSource(pIDataSource);
 264
 265         // and now it has the data
 266         wxDragResult rc = ConvertDragEffectToResult(GetDropEffect(grfKeyState));
 267         rc = m_pTarget->OnData(pt.x, pt.y, rc);
 268         if ( wxIsDragResultOk(rc) ) {
 269             // operation succeeded
 270             *pdwEffect = ConvertDragResultToEffect(rc);
 271         }
 272         //else: *pdwEffect is already DROPEFFECT_NONE
 273     }
 274     //else: OnDrop() returned FALSE, no need to copy data
 275
 276     // release the held object
 277     RELEASE_AND_NULL(m_pIDataObject);
 278
 279     return S_OK;
 280 }
 281
 282 // ============================================================================
 283 // wxDropTarget implementation
 284 // ============================================================================
 285
 286 // ----------------------------------------------------------------------------
 287 // ctor/dtor
 288 // ----------------------------------------------------------------------------
 289
 290 wxDropTarget::wxDropTarget(wxDataObject *dataObj)
 291             : wxDropTargetBase(dataObj)
 292 {
 293     // create an IDropTarget implementation which will notify us about d&d
 294     // operations.
 295     m_pIDropTarget = new wxIDropTarget(this);
 296     m_pIDropTarget->AddRef();
 297 }
 298
 299 wxDropTarget::~wxDropTarget()
 300 {
 301     ReleaseInterface(m_pIDropTarget);
 302 }
 303
 304 // ----------------------------------------------------------------------------
 305 // [un]register drop handler
 306 // ----------------------------------------------------------------------------
 307
 308 bool wxDropTarget::Register(WXHWND hwnd)
 309 {
 310     HRESULT hr = ::CoLockObjectExternal(m_pIDropTarget, TRUE, FALSE);
 311     if ( FAILED(hr) ) {
 312         wxLogApiError("CoLockObjectExternal", hr);
 313         return FALSE;
 314     }
 315
 316     hr = ::RegisterDragDrop((HWND) hwnd, m_pIDropTarget);
 317     if ( FAILED(hr) ) {
 318         ::CoLockObjectExternal(m_pIDropTarget, FALSE, FALSE);
 319
 320         wxLogApiError("RegisterDragDrop", hr);
 321         return FALSE;
 322     }
 323
 324     // we will need the window handle for coords transformation later
 325     m_pIDropTarget->SetHwnd((HWND)hwnd);
 326
 327     return TRUE;
 328 }
 329
 330 void wxDropTarget::Revoke(WXHWND hwnd)
 331 {
 332     HRESULT hr = ::RevokeDragDrop((HWND) hwnd);
 333
 334     if ( FAILED(hr) ) {
 335         wxLogApiError("RevokeDragDrop", hr);
 336     }
 337
 338     ::CoLockObjectExternal(m_pIDropTarget, FALSE, TRUE);
 339
 340     m_pIDropTarget->SetHwnd(0);
 341 }
 342
 343 // ----------------------------------------------------------------------------
 344 // base class pure virtuals
 345 // ----------------------------------------------------------------------------
 346
 347 // OnDrop() is called only if we previously returned TRUE from
 348 // IsAcceptedData(), so no need to check anything here
 349 bool wxDropTarget::OnDrop(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y))
 350 {
 351     return TRUE;
 352 }
 353
 354 // copy the data from the data source to the target data object
 355 bool wxDropTarget::GetData()
 356 {
 357     wxDataFormat format = GetSupportedFormat(m_pIDataSource);
 358     if ( format == wxDF_INVALID ) {
 359         // this is strange because IsAcceptedData() succeeded previously!
 360         wxFAIL_MSG(wxT("strange - did supported formats list change?"));
 361
 362         return FALSE;
 363     }
 364
 365     STGMEDIUM stm;
 366     FORMATETC fmtMemory;
 367     fmtMemory.cfFormat  = format;
 368     fmtMemory.ptd       = NULL;
 369     fmtMemory.dwAspect  = DVASPECT_CONTENT;
 370     fmtMemory.lindex    = -1;
 371     fmtMemory.tymed     = TYMED_HGLOBAL;  // TODO to add other media
 372
 373     bool rc = FALSE;
 374
 375     HRESULT hr = m_pIDataSource->GetData(&fmtMemory, &stm);
 376     if ( SUCCEEDED(hr) ) {
 377         IDataObject *dataObject = m_dataObject->GetInterface();
 378
 379         hr = dataObject->SetData(&fmtMemory, &stm, TRUE);
 380         if ( SUCCEEDED(hr) ) {
 381             rc = TRUE;
 382         }
 383         else {
 384             wxLogLastError(wxT("IDataObject::SetData()"));
 385         }
 386     }
 387     else {
 388         wxLogLastError(wxT("IDataObject::GetData()"));
 389     }
 390
 391     return rc;
 392 }
 393
 394 // ----------------------------------------------------------------------------
 395 // callbacks used by wxIDropTarget
 396 // ----------------------------------------------------------------------------
 397
 398 // we need a data source, so wxIDropTarget gives it to us using this function
 399 void wxDropTarget::SetDataSource(IDataObject *pIDataSource)
 400 {
 401     m_pIDataSource = pIDataSource;
 402 }
 403
 404 // determine if we accept data of this type
 405 bool wxDropTarget::IsAcceptedData(IDataObject *pIDataSource) const
 406 {
 407     return GetSupportedFormat(pIDataSource) != wxDF_INVALID;
 408 }
 409
 410 // ----------------------------------------------------------------------------
 411 // helper functions
 412 // ----------------------------------------------------------------------------
 413
 414 wxDataFormat wxDropTarget::GetSupportedFormat(IDataObject *pIDataSource) const
 415 {
 416     // this strucutre describes a data of any type (first field will be
 417     // changing) being passed through global memory block.
 418     static FORMATETC s_fmtMemory = {
 419         0,
 420         NULL,
 421         DVASPECT_CONTENT,
 422         -1,
 423         TYMED_HGLOBAL       // TODO is it worth supporting other tymeds here?
 424     };
 425
 426     // get the list of supported formats
 427     size_t nFormats = m_dataObject->GetFormatCount(wxDataObject::Set);
 428     wxDataFormat format, *formats;
 429     formats = nFormats == 1 ? &format :  new wxDataFormat[nFormats];
 430
 431     m_dataObject->GetAllFormats(formats, wxDataObject::Set);
 432
 433     // cycle through all supported formats
 434     size_t n;
 435     for ( n = 0; n < nFormats; n++ ) {
 436         s_fmtMemory.cfFormat = formats[n];
 437
 438         // NB: don't use SUCCEEDED macro here: QueryGetData returns S_FALSE
 439         //     for file drag and drop (format == CF_HDROP)
 440         if ( pIDataSource->QueryGetData(&s_fmtMemory) == S_OK ) {
 441             format = formats[n];
 442
 443             break;
 444         }
 445     }
 446
 447     if ( formats != &format ) {
 448         // free memory if we allocated it
 449         delete [] formats;
 450     }
 451
 452     return n < nFormats ? format : wxFormatInvalid;
 453 }
 454
 455 // ----------------------------------------------------------------------------
 456 // private functions
 457 // ----------------------------------------------------------------------------
 458
 459 static wxDragResult ConvertDragEffectToResult(DWORD dwEffect)
 460 {
 461     switch ( dwEffect ) {
 462         case DROPEFFECT_COPY:
 463             return wxDragCopy;
 464
 465         case DROPEFFECT_MOVE:
 466             return wxDragMove;
 467
 468         default:
 469             wxFAIL_MSG(wxT("invalid value in ConvertDragEffectToResult"));
 470             // fall through
 471
 472         case DROPEFFECT_NONE:
 473             return wxDragNone;
 474     }
 475 }
 476
 477 static DWORD ConvertDragResultToEffect(wxDragResult result)
 478 {
 479     switch ( result ) {
 480         case wxDragCopy:
 481             return DROPEFFECT_COPY;
 482
 483         case wxDragMove:
 484             return DROPEFFECT_MOVE;
 485
 486         default:
 487             wxFAIL_MSG(wxT("invalid value in ConvertDragResultToEffect"));
 488             // fall through
 489
 490         case wxDragNone:
 491             return DROPEFFECT_NONE;
 492     }
 493 }
 494
 495 #endif
 496  // wxUSE_DRAG_AND_DROP